This invention pertains to enclosed or partially enclosed vessels containing solutions or mechanical mixtures which are required to be blended, either continuously or intermittently. This is a very common need in a wide range of industries which includes the storage, mixing, processing and decanting of food products, pharmaceutical products and general chemical products of many types. These products are typically stored and transported in metal or plastic drums or bulk containers which have relatively small access ports on their top surface or on their lids, if applicable. There exists a need for an enclosed style mixer which can fit through these small ports without disassembly of the mixer or disassembly of the vessel lid. Further, there exists a need for a mixer apparatus that can effectively and efficiently blend the liquid-based contents throughout the volume of the vessel with the ability to entrain particles or liquid phases which tend to float, tend to sink or tend to remain static in the boundary layer against or near the vessel's inner walls or inner base.
The industry widely relies on an open-impeller type mixer design. This typically comprises a rigidly mounted motor or frame with a spinning shaft and impeller arrangement.
This existing technology fails to meet the full performance of the present invention for any or all of the following reasons: Open impeller mixers are required to be disassembled or are required to have collapsible impellers in order to pass through standard vessel ports. Open impeller mixers can physically damage vessels or vessel liners and may create sparking which presents risks in explosive environments. Open impeller mixers tend to cause rotation of the liquid media in the drum which causes aeration of the media and limits the mixing performance. Open impeller mixers cannot induce efficient flow at the boundary layers where the liquid media contacts the vessel interior base and interior walls. Open impeller mixers impart a reactive torque through their static frame elements, which must be restrained by means of bulky and cumbersome bracketry. Open impeller mixers require an excess of energy in order to impart mixing throughout large vessel volumes because the mixing is induced from a centralized point at the impeller with no strategic ducted distribution of media. Open impeller mixers are typically set in a fixed position which cannot reach the liquid media at low levels in the vessel, or will cause excessive aeration of the media once at low levels in the vessel.